(SOLVED) flash movies and screensaver

Hi.When I'm watching flash movies my screensaver is turining on after 1 hour it's maximum that I can set in gnome control center... how to change that time to 2 hours or turn off at all ? is it possible ? It's making me crazy because in half movie watching have to move mouse to see my movie again...

I've tried the LightsOn script mentioned in the article and had mixed results. I haven't tried the other program they mentioned (Caffeine), but I suppose you could use that and just set it to block the screensaver whenever flash-plugin-container is detected.